DISCERNMENT, DISCRIMINATION, PERCEPTION, PENETRATION, INSIGHT, ACUMEN mean a power to see what is not evident to the average mind.

DISCERNMENT stresses accuracy (as in reading character or motives or appreciating art).

e.g. the discernment to know true friends

DISCRIMINATION stresses the power to distinguish and select what is true or appropriate or excellent.

e.g. the discrimination that develops through listening to a lot of great music

PERCEPTION implies quick and often sympathetic discernment (as of shades of feeling).

e.g. a novelist of keen perception into human motives

PENETRATION implies a searching mind that goes beyond what is obvious or superficial.

e.g. lacks the penetration to see the scorn beneath their friendly smiles

INSIGHT suggests depth of discernment coupled with understanding sympathy.

e.g. a documentary providing insight into the plight of the homeless

ACUMEN implies characteristic penetration combined with keen practical judgment.

e.g. a director of reliable box-office acumen

the ability to make good judgments and quick decisions, typically in a particular domain:

(鋭敏な)判断［思考］力; (鋭い)洞察力; 鋭さ

e.g. business acumen.

late 16th century: from Latin, ‘sharpness, point’, from acuere ‘sharpen’ (see acute).